/**
 * makefsdata: Converts a directory structure for use with the lwIP httpd.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Jim Pettinato
 *         Simon Goldschmidt
 *
 * @todo:
 * - take TCP_MSS, LWIP_TCP_TIMESTAMPS and
 *   PAYLOAD_ALIGN_TYPE/PAYLOAD_ALIGNMENT as arguments
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>

#include "tinydir.h"

/** Makefsdata can generate *all* files deflate-compressed (where file size shrinks).
 * Since nearly all browsers support this, this is a good way to reduce ROM size.
 * To compress the files, "miniz.c" must be downloaded seperately.
 */
#ifndef MAKEFS_SUPPORT_DEFLATE
#define MAKEFS_SUPPORT_DEFLATE 0
#endif

#define COPY_BUFSIZE (1024*1024) /* 1 MByte */

#if MAKEFS_SUPPORT_DEFLATE
#include "../miniz.c"

typedef unsigned char uint8;
typedef unsigned short uint16;
typedef unsigned int uint;

#define my_max(a,b) (((a) > (b)) ? (a) : (b))
#define my_min(a,b) (((a) < (b)) ? (a) : (b))

/* COMP_OUT_BUF_SIZE is the size of the output buffer used during compression.
   COMP_OUT_BUF_SIZE must be >= 1 and <= OUT_BUF_SIZE */
#define COMP_OUT_BUF_SIZE COPY_BUFSIZE

/* OUT_BUF_SIZE is the size of the output buffer used during decompression.
   OUT_BUF_SIZE must be a power of 2 >= TINFL_LZ_DICT_SIZE (because the low-level decompressor not only writes, but reads from the output buffer as it decompresses) */
#define OUT_BUF_SIZE COPY_BUFSIZE
static uint8 s_outbuf[OUT_BUF_SIZE];
static uint8 s_checkbuf[OUT_BUF_SIZE];

/* tdefl_compressor contains all the state needed by the low-level compressor so it's a pretty big struct (~300k).
   This example makes it a global vs. putting it on the stack, of course in real-world usage you'll probably malloc() or new it. */
tdefl_compressor g_deflator;
tinfl_decompressor g_inflator;

int deflate_level = 10; /* default compression level, can be changed via command line */
#define USAGE_ARG_DEFLATE " [-defl<:compr_level>]"
#else /* MAKEFS_SUPPORT_DEFLATE */
#define USAGE_ARG_DEFLATE ""
#endif /* MAKEFS_SUPPORT_DEFLATE */

#ifdef WIN32

#define GETCWD(path, len)             GetCurrentDirectoryA(len, path)
#define CHDIR(path)                   SetCurrentDirectoryA(path)
#define CHDIR_SUCCEEDED(ret)          (ret == TRUE)

#elif __linux__

#define GETCWD(path, len)             getcwd(path, len)
#define CHDIR(path)                   chdir(path)
#define CHDIR_SUCCEEDED(ret)          (ret == 0)

#else

#error makefsdata not supported on this platform

#endif

#define NEWLINE     "\r\n"
#define NEWLINE_LEN 2

/* define this to get the header variables we use to build HTTP headers */
#define LWIP_HTTPD_DYNAMIC_HEADERS 1
#define LWIP_HTTPD_SSI             1
#include "lwip/init.h"
#include "../httpd_structs.h"
#include "lwip/apps/fs.h"

#include "../core/inet_chksum.c"
#include "../core/def.c"

/** (Your server name here) */
const char* serverID = "Server: "HTTPD_SERVER_AGENT"\r\n";
char serverIDBuffer[1024];

/* change this to suit your MEM_ALIGNMENT */
#define PAYLOAD_ALIGNMENT 4
/* set this to 0 to prevent aligning payload */
#define ALIGN_PAYLOAD 1
/* define this to a type that has the required alignment */
#define PAYLOAD_ALIGN_TYPE "unsigned int"
static int payload_alingment_dummy_counter = 0;

#define HEX_BYTES_PER_LINE 16

#define MAX_PATH_LEN 256

struct file_entry {
    struct file_entry* next;
    const char* filename_c;
};

int process_sub(FILE* data_file, FILE* struct_file);
int process_file(FILE* data_file, FILE* struct_file, const char* filename);
int file_write_http_header(FILE* data_file, const char* filename, int file_size, u16_t* http_hdr_len,
                           u16_t* http_hdr_chksum, u8_t provide_content_len, int is_compressed);
int file_put_ascii(FILE* file, const char* ascii_string, int len, int* i);
int s_put_ascii(char* buf, const char* ascii_string, int len, int* i);
void concat_files(const char* file1, const char* file2, const char* targetfile);
int check_path(char* path, size_t size);
static int checkSsiByFilelist(const char* filename_listfile);
static int ext_in_list(const char* filename, const char* ext_list);
static int file_to_exclude(const char* filename);
static int file_can_be_compressed(const char* filename);

/* 5 bytes per char + 3 bytes per line */
static char file_buffer_c[COPY_BUFSIZE * 5 + ((COPY_BUFSIZE / HEX_BYTES_PER_LINE) * 3)];

char curSubdir[MAX_PATH_LEN];
char lastFileVar[MAX_PATH_LEN];
char hdr_buf[4096];

unsigned char processSubs = 1;
unsigned char includeHttpHeader = 1;
unsigned char useHttp11 = 0;
unsigned char supportSsi = 1;
unsigned char precalcChksum = 0;
unsigned char includeLastModified = 0;
#if MAKEFS_SUPPORT_DEFLATE
unsigned char deflateNonSsiFiles = 0;
size_t deflatedBytesReduced = 0;
size_t overallDataBytes = 0;
#endif
const char* exclude_list = NULL;
const char* ncompress_list = NULL;

struct file_entry* first_file = NULL;
struct file_entry* last_file = NULL;

static char* ssi_file_buffer;
static char** ssi_file_lines;
static size_t ssi_file_num_lines;

static void print_usage(void)
{
    printf(" Usage: htmlgen [targetdir] [-s] [-e] [-11] [-nossi] [-ssi:<filename>] [-c] [-f:<filename>] [-m] [-svr:<name>] [-x:<ext_list>] [-xc:<ext_list>" USAGE_ARG_DEFLATE NEWLINE NEWLINE);
    printf("   targetdir: relative or absolute path to files to convert" NEWLINE);
    printf("   switch -s: toggle processing of subdirectories (default is on)" NEWLINE);
    printf("   switch -e: exclude HTTP header from file (header is created at runtime, default is off)" NEWLINE);
    printf("   switch -11: include HTTP 1.1 header (1.0 is default)" NEWLINE);
    printf("   switch -nossi: no support for SSI (cannot calculate Content-Length for SSI)" NEWLINE);
    printf("   switch -ssi: ssi filename (ssi support controlled by file list, not by extension)" NEWLINE);
    printf("   switch -c: precalculate checksums for all pages (default is off)" NEWLINE);
    printf("   switch -f: target filename (default is \"fsdata.c\")" NEWLINE);
    printf("   switch -m: include \"Last-Modified\" header based on file time" NEWLINE);
    printf("   switch -svr: server identifier sent in HTTP response header ('Server' field)" NEWLINE);
    printf("   switch -x: comma separated list of extensions of files to exclude (e.g., -x:json,txt)" NEWLINE);
    printf("   switch -xc: comma separated list of extensions of files to not compress (e.g., -xc:mp3,jpg)" NEWLINE);
#if MAKEFS_SUPPORT_DEFLATE
    printf("   switch -defl: deflate-compress all non-SSI files (with opt. compr.-level, default=10)" NEWLINE);
    printf("                 ATTENTION: browser has to support \"Content-Encoding: deflate\"!" NEWLINE);
#endif
    printf("   if targetdir not specified, htmlgen will attempt to" NEWLINE);
    printf("   process files in subdirectory 'fs'" NEWLINE);
}

int main(int argc, char* argv[])
{
    char path[MAX_PATH_LEN];
    char appPath[MAX_PATH_LEN];
    FILE* data_file;
    FILE* struct_file;
    int filesProcessed;
    int i;
    char targetfile[MAX_PATH_LEN];
    strcpy(targetfile, "fsdata.c");

    memset(path, 0, sizeof(path));
    memset(appPath, 0, sizeof(appPath));

    printf(NEWLINE " makefsdata - HTML to C source converter" NEWLINE);
    printf("     by Jim Pettinato               - circa 2003 " NEWLINE);
    printf("     extended by Simon Goldschmidt  - 2009 " NEWLINE NEWLINE);

    LWIP_ASSERT("sizeof(hdr_buf) must fit into an u16_t", sizeof(hdr_buf) <= 0xffff);

    strcpy(path, "fs");
    for (i = 1; i < argc; i++) {
        if (argv[i] == NULL) {
            continue;
        }
        if (argv[i][0] == '-') {
            if (strstr(argv[i], "-svr:") == argv[i]) {
                snprintf(serverIDBuffer, sizeof(serverIDBuffer), "Server: %s\r\n", &argv[i][5]);
                serverID = serverIDBuffer;
                printf("Using Server-ID: \"%s\"\n", serverID);
            }
            else if (!strcmp(argv[i], "-s")) {
                processSubs = 0;
            }
            else if (!strcmp(argv[i], "-e")) {
                includeHttpHeader = 0;
            }
            else if (!strcmp(argv[i], "-11")) {
                useHttp11 = 1;
            }
            else if (!strcmp(argv[i], "-nossi")) {
                supportSsi = 0;
            }
            else if (strstr(argv[i], "-ssi:") == argv[i]) {
                const char* ssi_list_filename = &argv[i][5];
                if (checkSsiByFilelist(ssi_list_filename)) {
                    printf("Reading list of SSI files from \"%s\"\n", ssi_list_filename);
                }
                else {
                    printf("Failed to load list of SSI files from \"%s\"\n", ssi_list_filename);
                }
            }
            else if (!strcmp(argv[i], "-c")) {
                precalcChksum = 1;
            }
            else if (strstr(argv[i], "-f:") == argv[i]) {
                strncpy(targetfile, &argv[i][3], sizeof(targetfile) - 1);
                targetfile[sizeof(targetfile) - 1] = 0;
                printf("Writing to file \"%s\"\n", targetfile);
            }
            else if (!strcmp(argv[i], "-m")) {
                includeLastModified = 1;
            }
            else if (!strcmp(argv[i], "-defl")) {
#if MAKEFS_SUPPORT_DEFLATE
                char* colon = strstr(argv[i], ":");
                if (colon) {
                    if (colon[1] != 0) {
                        int defl_level = atoi(&colon[1]);
                        if ((defl_level >= 0) && (defl_level <= 10)) {
                            deflate_level = defl_level;
                        }
                        else {
                            printf("ERROR: deflate level must be [0..10]" NEWLINE);
                            exit(0);
                        }
                    }
                }
                deflateNonSsiFiles = 1;
                printf("Deflating all non-SSI files with level %d (but only if size is reduced)" NEWLINE, deflate_level);
#else
                printf("WARNING: Deflate support is disabled\n");
#endif
            }
            else if (strstr(argv[i], "-x:") == argv[i]) {
                exclude_list = &argv[i][3];
                printf("Excluding files with extensions %s" NEWLINE, exclude_list);
            }
            else if (strstr(argv[i], "-xc:") == argv[i]) {
                ncompress_list = &argv[i][4];
                printf("Skipping compresion for files with extensions %s" NEWLINE, ncompress_list);
            }
            else if ((strstr(argv[i], "-?")) || (strstr(argv[i], "-h"))) {
                print_usage();
                exit(0);
            }
        }
        else if ((argv[i][0] == '/') && (argv[i][1] == '?') && (argv[i][2] == 0)) {
            print_usage();
            exit(0);
        }
        else {
            strncpy(path, argv[i], sizeof(path) - 1);
            path[sizeof(path) - 1] = 0;
        }
    }

    if (!check_path(path, sizeof(path))) {
        printf("Invalid path: \"%s\"." NEWLINE, path);
        exit(-1);
    }

    GETCWD(appPath, MAX_PATH_LEN);
    /* if command line param or subdir named 'fs' not found spout usage verbiage */
    if (!CHDIR_SUCCEEDED(CHDIR(path))) {
        /* if no subdir named 'fs' (or the one which was given) exists, spout usage verbiage */
        printf(" Failed to open directory \"%s\"." NEWLINE NEWLINE, path);
        print_usage();
        exit(-1);
    }
    CHDIR(appPath);

    printf("HTTP %sheader will %s statically included." NEWLINE,
           (includeHttpHeader ? (useHttp11 ? "1.1 " : "1.0 ") : ""),
           (includeHttpHeader ? "be" : "not be"));

    curSubdir[0] = '\0'; /* start off in web page's root directory - relative paths */
    printf("  Processing all files in directory %s", path);
    if (processSubs) {
        printf(" and subdirectories..." NEWLINE NEWLINE);
    }
    else {
        printf("..." NEWLINE NEWLINE);
    }

    data_file = fopen("fsdata.tmp", "wb");
    if (data_file == NULL) {
        printf("Failed to create file \"fsdata.tmp\"\n");
        exit(-1);
    }
    struct_file = fopen("fshdr.tmp", "wb");
    if (struct_file == NULL) {
        printf("Failed to create file \"fshdr.tmp\"\n");
        fclose(data_file);
        exit(-1);
    }

    CHDIR(path);

    fprintf(data_file, "#include \"lwip/apps/fs.h\"" NEWLINE);
    fprintf(data_file, "#include \"lwip/def.h\"" NEWLINE NEWLINE NEWLINE);

    fprintf(data_file, "#define file_NULL (struct fsdata_file *) NULL" NEWLINE NEWLINE NEWLINE);
    /* define FS_FILE_FLAGS_HEADER_INCLUDED to 1 if not defined (compatibility with older httpd/fs) */
    fprintf(data_file, "#ifndef FS_FILE_FLAGS_HEADER_INCLUDED" NEWLINE "#define FS_FILE_FLAGS_HEADER_INCLUDED 1" NEWLINE "#endif" NEWLINE);
    /* define FS_FILE_FLAGS_HEADER_PERSISTENT to 0 if not defined (compatibility with older httpd/fs: wasn't supported back then) */
    fprintf(data_file, "#ifndef FS_FILE_FLAGS_HEADER_PERSISTENT" NEWLINE "#define FS_FILE_FLAGS_HEADER_PERSISTENT 0" NEWLINE "#endif" NEWLINE);

    /* define alignment defines */
#if ALIGN_PAYLOAD
    fprintf(data_file, "/* FSDATA_FILE_ALIGNMENT: 0=off, 1=by variable, 2=by include */" NEWLINE "#ifndef FSDATA_FILE_ALIGNMENT" NEWLINE "#define FSDATA_FILE_ALIGNMENT 0" NEWLINE "#endif" NEWLINE);
#endif
    fprintf(data_file, "#ifndef FSDATA_ALIGN_PRE"  NEWLINE "#define FSDATA_ALIGN_PRE"  NEWLINE "#endif" NEWLINE);
    fprintf(data_file, "#ifndef FSDATA_ALIGN_POST" NEWLINE "#define FSDATA_ALIGN_POST" NEWLINE "#endif" NEWLINE);
#if ALIGN_PAYLOAD
    fprintf(data_file, "#if FSDATA_FILE_ALIGNMENT==2" NEWLINE "#include \"fsdata_alignment.h\"" NEWLINE "#endif" NEWLINE);
#endif

    sprintf(lastFileVar, "NULL");

    filesProcessed = process_sub(data_file, struct_file);

    /* data_file now contains all of the raw data.. now append linked list of
     * file header structs to allow embedded app to search for a file name */
    fprintf(data_file, NEWLINE NEWLINE);
    fprintf(struct_file, "#define FS_ROOT file_%s" NEWLINE, lastFileVar);
    fprintf(struct_file, "#define FS_NUMFILES %d" NEWLINE NEWLINE, filesProcessed);

    fclose(data_file);
    fclose(struct_file);

    CHDIR(appPath);
    /* append struct_file to data_file */
    printf(NEWLINE "Creating target file..." NEWLINE NEWLINE);
    concat_files("fsdata.tmp", "fshdr.tmp", targetfile);

    /* if succeeded, delete the temporary files */
    if (remove("fsdata.tmp") != 0) {
        printf("Warning: failed to delete fsdata.tmp\n");
    }
    if (remove("fshdr.tmp") != 0) {
        printf("Warning: failed to delete fshdr.tmp\n");
    }

    printf(NEWLINE "Processed %d files - done." NEWLINE, filesProcessed);
#if MAKEFS_SUPPORT_DEFLATE
    if (deflateNonSsiFiles) {
        printf("(Deflated total byte reduction: %d bytes -> %d bytes (%.02f%%)" NEWLINE,
               (int)overallDataBytes, (int)deflatedBytesReduced, (float)((deflatedBytesReduced * 100.0) / overallDataBytes));
    }
#endif
    printf(NEWLINE);

    while (first_file != NULL) {
        struct file_entry* fe = first_file;
        first_file = fe->next;
        free(fe);
    }

    if (ssi_file_buffer) {
        free(ssi_file_buffer);
    }
    if (ssi_file_lines) {
        free(ssi_file_lines);
    }

    return 0;
}

int check_path(char* path, size_t size)
{
    size_t slen;
    if (path[0] == 0) {
        /* empty */
        return 0;
    }
    slen = strlen(path);
    if (slen >= size) {
        /* not NULL-terminated */
        return 0;
    }
    while ((slen > 0) && ((path[slen] == '\\') || (path[slen] == '/'))) {
        /* path should not end with trailing backslash */
        path[slen] = 0;
        slen--;
    }
    if (slen == 0) {
        return 0;
    }
    return 1;
}

static void copy_file(const char* filename_in, FILE* fout)
{
    FILE* fin;
    size_t len;
    void* buf;
    fin = fopen(filename_in, "rb");
    if (fin == NULL) {
        printf("Failed to open file \"%s\"\n", filename_in);
        exit(-1);
    }
    buf = malloc(COPY_BUFSIZE);
    while ((len = fread(buf, 1, COPY_BUFSIZE, fin)) > 0) {
        fwrite(buf, 1, len, fout);
    }
    free(buf);
    fclose(fin);
}

void concat_files(const char* file1, const char* file2, const char* targetfile)
{
    FILE* fout;
    fout = fopen(targetfile, "wb");
    if (fout == NULL) {
        printf("Failed to open file \"%s\"\n", targetfile);
        exit(-1);
    }
    copy_file(file1, fout);
    copy_file(file2, fout);
    fclose(fout);
}

int process_sub(FILE* data_file, FILE* struct_file)
{
    tinydir_dir dir;
    int filesProcessed = 0;

    if (processSubs) {
        /* process subs recursively */
        size_t sublen = strlen(curSubdir);
        size_t freelen = sizeof(curSubdir) - sublen - 1;
        int ret;
        LWIP_ASSERT("sublen < sizeof(curSubdir)", sublen < sizeof(curSubdir));

        ret = tinydir_open_sorted(&dir, TINYDIR_STRING("."));

        if (ret == 0) {
            unsigned int i;
            for (i = 0; i < dir.n_files; i++) {
                tinydir_file file;

                ret = tinydir_readfile_n(&dir, &file, i);

                if (ret == 0) {
#if (defined _MSC_VER || defined __MINGW32__) && (defined _UNICODE)
                    size_t num_char_converted;
                    char currName[256];
                    wcstombs_s(&num_char_converted, currName, sizeof(currName), file.name, sizeof(currName));
#else
                    const char* currName = file.name;
#endif

                    if (currName[0] == '.') {
                        continue;
                    }
                    if (!file.is_dir) {
                        continue;
                    }
                    if (freelen > 0) {
                        CHDIR(currName);
                        strncat(curSubdir, "/", freelen);
                        strncat(curSubdir, currName, freelen - 1);
                        curSubdir[sizeof(curSubdir) - 1] = 0;
                        printf("processing subdirectory %s/..." NEWLINE, curSubdir);
                        filesProcessed += process_sub(data_file, struct_file);
                        CHDIR("..");
                        curSubdir[sublen] = 0;
                    }
                    else {
                        printf("WARNING: cannot process sub due to path length restrictions: \"%s/%s\"\n", curSubdir, currName);
                    }
                }
            }
        }

        ret = tinydir_open_sorted(&dir, TINYDIR_STRING("."));
        if (ret == 0) {
            unsigned int i;
            for (i = 0; i < dir.n_files; i++) {
                tinydir_file file;

                ret = tinydir_readfile_n(&dir, &file, i);

                if (ret == 0) {
                    if (!file.is_dir) {
#if (defined _MSC_VER || defined __MINGW32__) && (defined _UNICODE)
                        size_t num_char_converted;
                        char curName[256];
                        wcstombs_s(&num_char_converted, curName, sizeof(curName), file.name, sizeof(curName));
#else
                        const char* curName = file.name;
#endif

                        if (strcmp(curName, "fsdata.tmp") == 0) {
                            continue;
                        }
                        if (strcmp(curName, "fshdr.tmp") == 0) {
                            continue;
                        }
                        if (file_to_exclude(curName)) {
                            printf("skipping %s/%s by exclude list (-x option)..." NEWLINE, curSubdir, curName);
                            continue;
                        }

                        printf("processing %s/%s..." NEWLINE, curSubdir, curName);

                        if (process_file(data_file, struct_file, curName) < 0) {
                            printf(NEWLINE "Error... aborting" NEWLINE);
                            return -1;
                        }
                        filesProcessed++;
                    }
                }
            }
        }
    }

    return filesProcessed;
}

static u8_t* get_file_data(const char* filename, int* file_size, int can_be_compressed, int* is_compressed)
{
    FILE* inFile;
    size_t fsize = 0;
    u8_t* buf;
    size_t r;
    int rs;
    LWIP_UNUSED_ARG(r); /* for LWIP_NOASSERT */
    inFile = fopen(filename, "rb");
    if (inFile == NULL) {
        printf("Failed to open file \"%s\"\n", filename);
        exit(-1);
    }
    fseek(inFile, 0, SEEK_END);
    rs = ftell(inFile);
    if (rs < 0) {
        printf("ftell failed with %d\n", errno);
        exit(-1);
    }
    fsize = (size_t)rs;
    fseek(inFile, 0, SEEK_SET);
    buf = (u8_t*)malloc(fsize);
    LWIP_ASSERT("buf != NULL", buf != NULL);
    r = fread(buf, 1, fsize, inFile);
    LWIP_ASSERT("r == fsize", r == fsize);
    *file_size = fsize;
    *is_compressed = 0;
#if MAKEFS_SUPPORT_DEFLATE
    overallDataBytes += fsize;
    if (deflateNonSsiFiles) {
        if (can_be_compressed) {
            if (fsize < OUT_BUF_SIZE) {
                u8_t* ret_buf;
                tdefl_status status;
                size_t in_bytes = fsize;
                size_t out_bytes = OUT_BUF_SIZE;
                const void* next_in = buf;
                void* next_out = s_outbuf;
                /* create tdefl() compatible flags (we have to compose the low-level flags ourselves, or use tdefl_create_comp_flags_from_zip_params() but that means MINIZ_NO_ZLIB_APIS can't be defined). */
                mz_uint comp_flags = s_tdefl_num_probes[MZ_MIN(10, deflate_level)] | ((deflate_level <= 3) ? TDEFL_GREEDY_PARSING_FLAG : 0);
                if (!deflate_level) {
                    comp_flags |= TDEFL_FORCE_ALL_RAW_BLOCKS;
                }
                status = tdefl_init(&g_deflator, NULL, NULL, comp_flags);
                if (status != TDEFL_STATUS_OKAY) {
                    printf("tdefl_init() failed!\n");
                    exit(-1);
                }
                memset(s_outbuf, 0, sizeof(s_outbuf));
                status = tdefl_compress(&g_deflator, next_in, &in_bytes, next_out, &out_bytes, TDEFL_FINISH);
                if (status != TDEFL_STATUS_DONE) {
                    printf("deflate failed: %d\n", status);
                    exit(-1);
                }
                LWIP_ASSERT("out_bytes <= COPY_BUFSIZE", out_bytes <= OUT_BUF_SIZE);
                if (out_bytes < fsize) {
                    ret_buf = (u8_t*)malloc(out_bytes);
                    LWIP_ASSERT("ret_buf != NULL", ret_buf != NULL);
                    memcpy(ret_buf, s_outbuf, out_bytes);
                    {
                        /* sanity-check compression be inflating and comparing to the original */
                        tinfl_status dec_status;
                        tinfl_decompressor inflator;
                        size_t dec_in_bytes = out_bytes;
                        size_t dec_out_bytes = OUT_BUF_SIZE;
                        next_out = s_checkbuf;

                        tinfl_init(&inflator);
                        memset(s_checkbuf, 0, sizeof(s_checkbuf));
                        dec_status = tinfl_decompress(&inflator, (const mz_uint8*)ret_buf, &dec_in_bytes, s_checkbuf, (mz_uint8*)next_out, &dec_out_bytes, 0);
                        LWIP_ASSERT("tinfl_decompress failed", dec_status == TINFL_STATUS_DONE);
                        LWIP_ASSERT("tinfl_decompress size mismatch", fsize == dec_out_bytes);
                        LWIP_ASSERT("decompressed memcmp failed", !memcmp(s_checkbuf, buf, fsize));
                    }
                    /* free original buffer, use compressed data + size */
                    free(buf);
                    buf = ret_buf;
                    *file_size = out_bytes;
                    printf(" - deflate: %d bytes -> %d bytes (%.02f%%)" NEWLINE, (int)fsize, (int)out_bytes, (float)((out_bytes * 100.0) / fsize));
                    deflatedBytesReduced += (size_t)(fsize - out_bytes);
                    *is_compressed = 1;
                }
                else {
                    printf(" - uncompressed: (would be %d bytes larger using deflate)" NEWLINE, (int)(out_bytes - fsize));
                }
            }
            else {
                printf(" - uncompressed: (file is larger than deflate bufer)" NEWLINE);
            }
        }
        else {
            printf(" - cannot be compressed" NEWLINE);
        }
    }
#else
    LWIP_UNUSED_ARG(can_be_compressed);
#endif
    fclose(inFile);
    return buf;
}

static void process_file_data(FILE* data_file, u8_t* file_data, size_t file_size)
{
    size_t written, i, src_off = 0;
    size_t off = 0;
    LWIP_UNUSED_ARG(written); /* for LWIP_NOASSERT */
    for (i = 0; i < file_size; i++) {
        LWIP_ASSERT("file_buffer_c overflow", off < sizeof(file_buffer_c) - 5);
        sprintf(&file_buffer_c[off], "0x%02x,", file_data[i]);
        off += 5;
        if ((++src_off % HEX_BYTES_PER_LINE) == 0) {
            LWIP_ASSERT("file_buffer_c overflow", off < sizeof(file_buffer_c) - NEWLINE_LEN);
            memcpy(&file_buffer_c[off], NEWLINE, NEWLINE_LEN);
            off += NEWLINE_LEN;
        }
        if (off + 20 >= sizeof(file_buffer_c)) {
            written = fwrite(file_buffer_c, 1, off, data_file);
            LWIP_ASSERT("written == off", written == off);
            off = 0;
        }
    }
    written = fwrite(file_buffer_c, 1, off, data_file);
    LWIP_ASSERT("written == off", written == off);
}

static int write_checksums(FILE* struct_file, const char* varname,
                           u16_t hdr_len, u16_t hdr_chksum, const u8_t* file_data, size_t file_size)
{
    int chunk_size = TCP_MSS;
    int offset, src_offset;
    size_t len;
    int i = 0;
#if LWIP_TCP_TIMESTAMPS
    /* when timestamps are used, usable space is 12 bytes less per segment */
    chunk_size -= 12;
#endif

    fprintf(struct_file, "#if HTTPD_PRECALCULATED_CHECKSUM" NEWLINE);
    fprintf(struct_file, "const struct fsdata_chksum chksums_%s[] = {" NEWLINE, varname);

    if (hdr_len > 0) {
        /* add checksum for HTTP header */
        fprintf(struct_file, "{%d, 0x%04x, %d}," NEWLINE, 0, hdr_chksum, hdr_len);
        i++;
    }
    src_offset = 0;
    for (offset = hdr_len; ; offset += len) {
        unsigned short chksum;
        const void* data = (const void*)&file_data[src_offset];
        len = LWIP_MIN(chunk_size, (int)file_size - src_offset);
        if (len == 0) {
            break;
        }
        chksum = ~inet_chksum(data, (u16_t)len);
        /* add checksum for data */
        fprintf(struct_file, "{%d, 0x%04x, %"SZT_F"}," NEWLINE, offset, chksum, len);
        i++;
    }
    fprintf(struct_file, "};" NEWLINE);
    fprintf(struct_file, "#endif /* HTTPD_PRECALCULATED_CHECKSUM */" NEWLINE);
    return i;
}

static int is_valid_char_for_c_var(char x)
{
    if (((x >= 'A') && (x <= 'Z')) ||
            ((x >= 'a') && (x <= 'z')) ||
            ((x >= '0') && (x <= '9')) ||
            (x == '_')) {
        return 1;
    }
    return 0;
}

static void fix_filename_for_c(char* qualifiedName, size_t max_len)
{
    struct file_entry* f;
    size_t len = strlen(qualifiedName);
    char* new_name = (char*)malloc(len + 2);
    int filename_ok;
    int cnt = 0;
    size_t i;
    if (len + 3 == max_len) {
        printf("File name too long: \"%s\"\n", qualifiedName);
        exit(-1);
    }
    strcpy(new_name, qualifiedName);
    for (i = 0; i < len; i++) {
        if (!is_valid_char_for_c_var(new_name[i])) {
            new_name[i] = '_';
        }
    }
    do {
        filename_ok = 1;
        for (f = first_file; f != NULL; f = f->next) {
            if (!strcmp(f->filename_c, new_name)) {
                filename_ok = 0;
                cnt++;
                /* try next unique file name */
                sprintf(&new_name[len], "%d", cnt);
                break;
            }
        }
    } while (!filename_ok && (cnt < 999));
    if (!filename_ok) {
        printf("Failed to get unique file name: \"%s\"\n", qualifiedName);
        exit(-1);
    }
    strcpy(qualifiedName, new_name);
    free(new_name);
}

static void register_filename(const char* qualifiedName)
{
    struct file_entry* fe = (struct file_entry*)malloc(sizeof(struct file_entry));
    fe->filename_c = strdup(qualifiedName);
    fe->next = NULL;
    if (first_file == NULL) {
        first_file = last_file = fe;
    }
    else {
        last_file->next = fe;
        last_file = fe;
    }
}

static int checkSsiByFilelist(const char* filename_listfile)
{
    FILE* f = fopen(filename_listfile, "r");
    if (f != NULL) {
        char* buf;
        long rs;
        size_t fsize, readcount;
        size_t i, l, num_lines;
        char** lines;
        int state;

        fseek(f, 0, SEEK_END);
        rs = ftell(f);
        if (rs < 0) {
            printf("ftell failed with %d\n", errno);
            fclose(f);
            return 0;
        }
        fsize = (size_t)rs;
        fseek(f, 0, SEEK_SET);
        buf = (char*)malloc(fsize);
        if (!buf) {
            printf("failed to allocate ssi file buffer\n");
            fclose(f);
            return 0;
        }
        memset(buf, 0, fsize);
        readcount = fread(buf, 1, fsize, f);
        fclose(f);
        if ((readcount > fsize) || !readcount) {
            printf("failed to read data from ssi file\n");
            free(buf);
            return 0;
        }

        /* first pass: get the number of lines (and convert newlines to '0') */
        num_lines = 1;
        for (i = 0; i < readcount; i++) {
            if (buf[i] == '\n') {
                num_lines++;
                buf[i] = 0;
            }
            else if (buf[i] == '\r') {
                buf[i] = 0;
            }
        }
        /* allocate the line pointer array */
        lines = (char**)malloc(sizeof(char*) * num_lines);
        if (!lines) {
            printf("failed to allocate ssi line buffer\n");
            free(buf);
            return 0;
        }
        memset(lines, 0, sizeof(char*) * num_lines);
        l = 0;
        state = 0;
        for (i = 0; i < readcount; i++) {
            if (state) {
                /* waiting for null */
                if (buf[i] == 0) {
                    state = 0;
                }
            }
            else {
                /* waiting for beginning of new string */
                if (buf[i] != 0) {
                    LWIP_ASSERT("lines array overflow", l < num_lines);
                    lines[l] = &buf[i];
                    state = 1;
                    l++;
                }
            }
        }
        LWIP_ASSERT("lines array overflow", l < num_lines);

        ssi_file_buffer = buf;
        ssi_file_lines = lines;
        ssi_file_num_lines = l;
    }
    return 0;
}

static int is_ssi_file(const char* filename)
{
    if (supportSsi) {
        if (ssi_file_buffer) {
            /* compare by list */
            size_t i;
            int ret = 0;
            /* build up the relative path to this file */
            size_t sublen = strlen(curSubdir);
            size_t freelen = sizeof(curSubdir) - sublen - 1;
            strncat(curSubdir, "/", freelen);
            strncat(curSubdir, filename, freelen - 1);
            curSubdir[sizeof(curSubdir) - 1] = 0;
            for (i = 0; i < ssi_file_num_lines; i++) {
                const char* listed_file = ssi_file_lines[i];
                /* compare without the leading '/' */
                if (!strcmp(&curSubdir[1], listed_file)) {
                    ret = 1;
                }
            }
            curSubdir[sublen] = 0;
            return ret;
        }
        else {
            /* check file extension */
            size_t loop;
            for (loop = 0; loop < NUM_SHTML_EXTENSIONS; loop++) {
                if (strstr(filename, g_pcSSIExtensions[loop])) {
                    return 1;
                }
            }
        }
    }
    return 0;
}

static int ext_in_list(const char* filename, const char* ext_list)
{
    int found = 0;
    const char* ext = ext_list;
    if (ext_list == NULL) {
        return 0;
    }
    while(*ext != '\0') {
        const char* comma = strchr(ext, ',');
        size_t ext_size;
        size_t filename_size = strlen(filename);
        if (comma == NULL) {
            comma = strchr(ext, '\0');
        }
        ext_size = comma - ext;
        if ((filename[filename_size - ext_size - 1] == '.') &&
                !strncmp(&filename[filename_size - ext_size], ext, ext_size)) {
            found = 1;
            break;
        }
        ext = comma + 1;
    }

    return found;
}

static int file_to_exclude(const char* filename)
{
    return (exclude_list != NULL) && ext_in_list(filename, exclude_list);
}

static int file_can_be_compressed(const char* filename)
{
    return (ncompress_list == NULL) || !ext_in_list(filename, ncompress_list);
}

int process_file(FILE* data_file, FILE* struct_file, const char* filename)
{
    char varname[MAX_PATH_LEN];
    int i = 0;
    char qualifiedName[MAX_PATH_LEN];
    int file_size;
    u16_t http_hdr_chksum = 0;
    u16_t http_hdr_len = 0;
    int chksum_count = 0;
    u8_t flags = 0;
    u8_t has_content_len;
    u8_t* file_data;
    int is_ssi;
    int can_be_compressed;
    int is_compressed = 0;
    int flags_printed;

    /* create qualified name (@todo: prepend slash or not?) */
    sprintf(qualifiedName, "%s/%s", curSubdir, filename);
    /* create C variable name */
    strcpy(varname, qualifiedName);
    /* convert slashes & dots to underscores */
    fix_filename_for_c(varname, MAX_PATH_LEN);
    register_filename(varname);
#if ALIGN_PAYLOAD
    /* to force even alignment of array, type 1 */
    fprintf(data_file, "#if FSDATA_FILE_ALIGNMENT==1" NEWLINE);
    fprintf(data_file, "static const " PAYLOAD_ALIGN_TYPE " dummy_align_%s = %d;" NEWLINE, varname, payload_alingment_dummy_counter++);
    fprintf(data_file, "#endif" NEWLINE);
#endif /* ALIGN_PAYLOAD */
    fprintf(data_file, "static const unsigned char FSDATA_ALIGN_PRE data_%s[] FSDATA_ALIGN_POST = {" NEWLINE, varname);
    /* encode source file name (used by file system, not returned to browser) */
    fprintf(data_file, "/* %s (%"SZT_F" chars) */" NEWLINE, qualifiedName, strlen(qualifiedName) + 1);
    file_put_ascii(data_file, qualifiedName, strlen(qualifiedName) + 1, &i);
#if ALIGN_PAYLOAD
    /* pad to even number of bytes to assure payload is on aligned boundary */
    while (i % PAYLOAD_ALIGNMENT != 0) {
        fprintf(data_file, "0x%02x,", 0);
        i++;
    }
#endif /* ALIGN_PAYLOAD */
    fprintf(data_file, NEWLINE);

    is_ssi = is_ssi_file(filename);
    if (is_ssi) {
        flags |= FS_FILE_FLAGS_SSI;
    }
    has_content_len = !is_ssi;
    can_be_compressed = includeHttpHeader && !is_ssi && file_can_be_compressed(filename);
    file_data = get_file_data(filename, &file_size, can_be_compressed, &is_compressed);
    if (includeHttpHeader) {
        file_write_http_header(data_file, filename, file_size, &http_hdr_len, &http_hdr_chksum, has_content_len, is_compressed);
        flags |= FS_FILE_FLAGS_HEADER_INCLUDED;
        if (has_content_len) {
            flags |= FS_FILE_FLAGS_HEADER_PERSISTENT;
            if (useHttp11) {
                flags |= FS_FILE_FLAGS_HEADER_HTTPVER_1_1;
            }
        }
    }
    if (precalcChksum) {
        chksum_count = write_checksums(struct_file, varname, http_hdr_len, http_hdr_chksum, file_data, file_size);
    }

    /* build declaration of struct fsdata_file in temp file */
    fprintf(struct_file, "const struct fsdata_file file_%s[] = { {" NEWLINE, varname);
    fprintf(struct_file, "file_%s," NEWLINE, lastFileVar);
    fprintf(struct_file, "data_%s," NEWLINE, varname);
    fprintf(struct_file, "data_%s + %d," NEWLINE, varname, i);
    fprintf(struct_file, "sizeof(data_%s) - %d," NEWLINE, varname, i);

    flags_printed = 0;
    if (flags & FS_FILE_FLAGS_HEADER_INCLUDED) {
        fputs("FS_FILE_FLAGS_HEADER_INCLUDED", struct_file);
        flags_printed = 1;
    }
    if (flags & FS_FILE_FLAGS_HEADER_PERSISTENT) {
        if (flags_printed) {
            fputs(" | ", struct_file);
        }
        fputs("FS_FILE_FLAGS_HEADER_PERSISTENT", struct_file);
        flags_printed = 1;
    }
    if (flags & FS_FILE_FLAGS_HEADER_HTTPVER_1_1) {
        if (flags_printed) {
            fputs(" | ", struct_file);
        }
        fputs("FS_FILE_FLAGS_HEADER_HTTPVER_1_1", struct_file);
        flags_printed = 1;
    }
    if (flags & FS_FILE_FLAGS_SSI) {
        if (flags_printed) {
            fputs(" | ", struct_file);
        }
        fputs("FS_FILE_FLAGS_SSI", struct_file);
        flags_printed = 1;
    }
    if (!flags_printed) {
        fputs("0", struct_file);
    }
    fputs("," NEWLINE, struct_file);
    if (precalcChksum) {
        fprintf(struct_file, "#if HTTPD_PRECALCULATED_CHECKSUM" NEWLINE);
        fprintf(struct_file, "%d, chksums_%s," NEWLINE, chksum_count, varname);
        fprintf(struct_file, "#endif /* HTTPD_PRECALCULATED_CHECKSUM */" NEWLINE);
    }
    fprintf(struct_file, "}};" NEWLINE NEWLINE);
    strcpy(lastFileVar, varname);

    /* write actual file contents */
    i = 0;
    fprintf(data_file, NEWLINE "/* raw file data (%d bytes) */" NEWLINE, file_size);
    process_file_data(data_file, file_data, file_size);
    fprintf(data_file, "};" NEWLINE NEWLINE);
    free(file_data);
    return 0;
}

int file_write_http_header(FILE* data_file, const char* filename, int file_size, u16_t* http_hdr_len,
                           u16_t* http_hdr_chksum, u8_t provide_content_len, int is_compressed)
{
    int i = 0;
    int response_type = HTTP_HDR_OK;
    const char* file_type;
    const char* cur_string;
    size_t cur_len;
    int written = 0;
    size_t hdr_len = 0;
    u16_t acc;
    const char* file_ext;
    size_t j;
    u8_t provide_last_modified = includeLastModified;

    memset(hdr_buf, 0, sizeof(hdr_buf));

    if (useHttp11) {
        response_type = HTTP_HDR_OK_11;
    }

    fprintf(data_file, NEWLINE "/* HTTP header */");
    if (strstr(filename, "404") == filename) {
        response_type = HTTP_HDR_NOT_FOUND;
        if (useHttp11) {
            response_type = HTTP_HDR_NOT_FOUND_11;
        }
    }
    else if (strstr(filename, "400") == filename) {
        response_type = HTTP_HDR_BAD_REQUEST;
        if (useHttp11) {
            response_type = HTTP_HDR_BAD_REQUEST_11;
        }
    }
    else if (strstr(filename, "501") == filename) {
        response_type = HTTP_HDR_NOT_IMPL;
        if (useHttp11) {
            response_type = HTTP_HDR_NOT_IMPL_11;
        }
    }
    cur_string = g_psHTTPHeaderStrings[response_type];
    cur_len = strlen(cur_string);
    fprintf(data_file, NEWLINE "/* \"%s\" (%"SZT_F" bytes) */" NEWLINE, cur_string, cur_len);
    written += file_put_ascii(data_file, cur_string, cur_len, &i);
    i = 0;
    if (precalcChksum) {
        memcpy(&hdr_buf[hdr_len], cur_string, cur_len);
        hdr_len += cur_len;
    }

    cur_string = serverID;
    cur_len = strlen(cur_string);
    fprintf(data_file, NEWLINE "/* \"%s\" (%"SZT_F" bytes) */" NEWLINE, cur_string, cur_len);
    written += file_put_ascii(data_file, cur_string, cur_len, &i);
    i = 0;
    if (precalcChksum) {
        memcpy(&hdr_buf[hdr_len], cur_string, cur_len);
        hdr_len += cur_len;
    }

    file_ext = filename;
    if (file_ext != NULL) {
        while (strstr(file_ext, ".") != NULL) {
            file_ext = strstr(file_ext, ".");
            file_ext++;
        }
    }
    if ((file_ext == NULL) || (*file_ext == 0)) {
        printf("failed to get extension for file \"%s\", using default.\n", filename);
        file_type = HTTP_HDR_DEFAULT_TYPE;
    }
    else {
        file_type = NULL;
        for (j = 0; j < NUM_HTTP_HEADERS; j++) {
            if (!strcmp(file_ext, g_psHTTPHeaders[j].extension)) {
                file_type = g_psHTTPHeaders[j].content_type;
                break;
            }
        }
        if (file_type == NULL) {
            printf("failed to get file type for extension \"%s\", using default.\n", file_ext);
            file_type = HTTP_HDR_DEFAULT_TYPE;
        }
    }

    /* Content-Length is used for persistent connections in HTTP/1.1 but also for
       download progress in older versions
       @todo: just use a big-enough buffer and let the HTTPD send spaces? */
    if (provide_content_len) {
        char intbuf[MAX_PATH_LEN];
        int content_len = file_size;
        memset(intbuf, 0, sizeof(intbuf));
        cur_string = g_psHTTPHeaderStrings[HTTP_HDR_CONTENT_LENGTH];
        cur_len = strlen(cur_string);
        fprintf(data_file, NEWLINE "/* \"%s%d\r\n\" (%"SZT_F"+ bytes) */" NEWLINE, cur_string, content_len, cur_len + 2);
        written += file_put_ascii(data_file, cur_string, cur_len, &i);
        if (precalcChksum) {
            memcpy(&hdr_buf[hdr_len], cur_string, cur_len);
            hdr_len += cur_len;
        }

        lwip_itoa(intbuf, sizeof(intbuf), content_len);
        strcat(intbuf, "\r\n");
        cur_len = strlen(intbuf);
        written += file_put_ascii(data_file, intbuf, cur_len, &i);
        i = 0;
        if (precalcChksum) {
            memcpy(&hdr_buf[hdr_len], intbuf, cur_len);
            hdr_len += cur_len;
        }
    }
    if (provide_last_modified) {
        char modbuf[256];
        struct stat stat_data;
        struct tm* t;
        memset(modbuf, 0, sizeof(modbuf));
        memset(&stat_data, 0, sizeof(stat_data));
        cur_string = modbuf;
        strcpy(modbuf, "Last-Modified: ");
        if (stat(filename, &stat_data) != 0) {
            printf("stat(%s) failed with error %d\n", filename, errno);
            exit(-1);
        }
        t = gmtime(&stat_data.st_mtime);
        if (t == NULL) {
            printf("gmtime() failed with error %d\n", errno);
            exit(-1);
        }
        strftime(&modbuf[15], sizeof(modbuf) - 15, "%a, %d %b %Y %H:%M:%S GMT", t);
        cur_len = strlen(cur_string);
        fprintf(data_file, NEWLINE "/* \"%s\"\r\n\" (%"SZT_F"+ bytes) */" NEWLINE, cur_string, cur_len + 2);
        written += file_put_ascii(data_file, cur_string, cur_len, &i);
        if (precalcChksum) {
            memcpy(&hdr_buf[hdr_len], cur_string, cur_len);
            hdr_len += cur_len;
        }

        modbuf[0] = 0;
        strcat(modbuf, "\r\n");
        cur_len = strlen(modbuf);
        written += file_put_ascii(data_file, modbuf, cur_len, &i);
        i = 0;
        if (precalcChksum) {
            memcpy(&hdr_buf[hdr_len], modbuf, cur_len);
            hdr_len += cur_len;
        }
    }

    /* HTTP/1.1 implements persistent connections */
    if (useHttp11) {
        if (provide_content_len) {
            cur_string = g_psHTTPHeaderStrings[HTTP_HDR_CONN_KEEPALIVE];
        }
        else {
            /* no Content-Length available, so a persistent connection is no possible
               because the client does not know the data length */
            cur_string = g_psHTTPHeaderStrings[HTTP_HDR_CONN_CLOSE];
        }
        cur_len = strlen(cur_string);
        fprintf(data_file, NEWLINE "/* \"%s\" (%"SZT_F" bytes) */" NEWLINE, cur_string, cur_len);
        written += file_put_ascii(data_file, cur_string, cur_len, &i);
        i = 0;
        if (precalcChksum) {
            memcpy(&hdr_buf[hdr_len], cur_string, cur_len);
            hdr_len += cur_len;
        }
    }

#if MAKEFS_SUPPORT_DEFLATE
    if (is_compressed) {
        /* tell the client about the deflate encoding */
        LWIP_ASSERT("error", deflateNonSsiFiles);
        cur_string = "Content-Encoding: deflate\r\n";
        cur_len = strlen(cur_string);
        fprintf(data_file, NEWLINE "/* \"%s\" (%d bytes) */" NEWLINE, cur_string, cur_len);
        written += file_put_ascii(data_file, cur_string, cur_len, &i);
        i = 0;
    }
#else
    LWIP_UNUSED_ARG(is_compressed);
#endif

    /* write content-type, ATTENTION: this includes the double-CRLF! */
    cur_string = file_type;
    cur_len = strlen(cur_string);
    fprintf(data_file, NEWLINE "/* \"%s\" (%"SZT_F" bytes) */" NEWLINE, cur_string, cur_len);
    written += file_put_ascii(data_file, cur_string, cur_len, &i);
    i = 0;

    /* ATTENTION: headers are done now (double-CRLF has been written!) */

    if (precalcChksum) {
        LWIP_ASSERT("hdr_len + cur_len <= sizeof(hdr_buf)", hdr_len + cur_len <= sizeof(hdr_buf));
        memcpy(&hdr_buf[hdr_len], cur_string, cur_len);
        hdr_len += cur_len;

        LWIP_ASSERT("strlen(hdr_buf) == hdr_len", strlen(hdr_buf) == hdr_len);
        acc = ~inet_chksum(hdr_buf, (u16_t)hdr_len);
        *http_hdr_len = (u16_t)hdr_len;
        *http_hdr_chksum = acc;
    }

    return written;
}

int file_put_ascii(FILE* file, const char* ascii_string, int len, int* i)
{
    int x;
    for (x = 0; x < len; x++) {
        unsigned char cur = ascii_string[x];
        fprintf(file, "0x%02x,", cur);
        if ((++(*i) % HEX_BYTES_PER_LINE) == 0) {
            fprintf(file, NEWLINE);
        }
    }
    return len;
}

int s_put_ascii(char* buf, const char* ascii_string, int len, int* i)
{
    int x;
    int idx = 0;
    for (x = 0; x < len; x++) {
        unsigned char cur = ascii_string[x];
        sprintf(&buf[idx], "0x%02x,", cur);
        idx += 5;
        if ((++(*i) % HEX_BYTES_PER_LINE) == 0) {
            sprintf(&buf[idx], NEWLINE);
            idx += NEWLINE_LEN;
        }
    }
    return len;
}
